This is meant for ham radio fellows who would like to get an impression of what can be
expected from a very simple SDR RX hardware (e.g. SoftRock Lite II) and a corresponding
SDR Software program ("Winrad" Freeware, see below), without the need of owning any
SDR radio hardware!

The CW .wav file below is targeting CW OPs, as the .wav file below represents a spectrum
of the European 40m CW band during a Region 1 CW contest in 2009, no SSB.

Within a few minutes you'll find yourself in the middle of a contest and are able to tune-in
CW stations as if it was real-time.

The SSB .wav file is just a random recording of a section in the 20m SSB band.
Receiver used for this recording was a PMSDR receiver which is available as an easy to
build kit from IW3AUT.

PC hardware requirements are very modest: any XP (or up) PC with integrated stereo sound
card should be ok.

Comment:

Just ignore the frequency indication which is not showing the correct frequency as this is
just a .wav file playback without a radio connected.

The S-meter does not show the correct readings at the time when I made the recordings,
as it is not calibrated to your PC/PC sound card.

** Special courtesy for Rich **

Down below is the link to an I/Q recording file of parts of the 2009 IARU Region 1 CW contest.

Update 03-July-2011:I have added a link to another .wav file below with a random recording of a section of the 20m SSB band. If the SSB sidebands are mixed-up (the other way around) just go to the Winrad menu 'show options' andselect 'swap I and Q channels'. Center frequency of the recording is 14.181 MHz.

It is interesting to watch and analyze the various CW and SSB signals in the waterfall display.
E.g. compare opposite sideband surpression (on the other side, i.e. lower side of the carrier frequency)
of the various SSB (USB) signals and bandwidth of the CW signals (key clicks?).

** Please read on before jumping to the link directly. You'll get to there anyway! **

File size is about 18 MB, file format is .wav

Recording date, time and frequency for the CW file:

2009-Sept-13, starting at 20:25:19Z (UTC), center frequency is 7020 KHz
The file name corresponds to this data.

2. Download my .wav file from below (right-click on link and "save file as...") and save it
onto your PC hard disk. Copy this .wav file to the "Winrad" directory (to where you've
installed "Winrad" just before) so that you'll find the .wav file more easily from within
"Winrad" afterwards.

3. Start "Winrad" by double-clicking on the "Winrad" icon.

4. Within "Winrad", click on "Show Options". In the menu, point your mouse on "Select Input"
and click on "WAV file...". Select my .wav file in the dialog box by double-clicking the file
name. You are now back on the "Winrad" screen.

Select "CW" and click on the play-back button (green triangle). You'll now see the spectrum and
waterfall of a frequency range starting from about 7,000 to 7,040 KHz, packed with CW stations.
Adjust your sound card audio volume so that you'll hear the CW signals from the speaker.

Use your mouse pointer to select a signal from within the spectrum or water-fall window (point and
left-click on a signal). You can use your mouse wheel to scroll the frequency up or down.
Select "10 Hz" steps by clicking on the corresponding button at "Wheel step".

You can change the RX bandwidth by drag and drop of the red passband curve in the passband
window. You'll find the passband filter selectivity to be razor-sharp!

Other functions of "Winrad" are more or less self-explanatory.

When the recording stops just hit the green play-back button again.

Have fun!

Klaus, DK3QN

right-click on the link below and save file to your "Winrad" directory: